Gold particles help scientists find defects

Researchers at Vanderbilt University in the U.S. have developed a technique that allows gold to actually ‘shine’ inside 3D printed parts to highlight any problems.

The scientists used particles of gold that are 100,000 times thinner than a human hair and that show up as a deep maroon colour. The elements were embedded inside printing material to see whether it could help flag defects.

The process involves mixing the gold nanoparticles with a dissolved plastic polymer, dispersing it throughout the medium. When it dries and hardens, the plastic is extruded or pressed into gold nanoparticle-filled polymer filaments, or thin tubing, which can then be used in standard 3D printers.

After a part is printed, it goes into a special UV-Vis spectrophotometer to inspect for defects.

“We’re using the absorbance properties of the embedded gold nanoparticles,” said in a press release Cole Brubaker, civil engineering graduate student, and lead scientist in this research. “You just scan light across the surface of the sample and see where the absorbance decreases inside, signaling a defect in that material. A defect can be found with one single nondestructive measurement. It’s very quick. It takes just a matter of seconds. We don’t have to rely on large sensing systems that have sensors placed all over the part.”

Brubaker and his team believe that their solution is critical in a world where 3D printed materials are becoming increasingly common, from consumer goods and products to demonstrations of 3D-printed automobiles and homes.